By default, the yearly calendar (the "planned downtimes") takes priority over any calendar exception.
If you allocate a special calendar to a machine during a company planned downtime, the planning process does not take this special calendar into account.
Business configuration parameter EXCEPT_DOWNTIMES_HAVE_PRIORITY_ON_PLANNED_DOWNTIMES offers to give priority to special calendars instead.
Planning Administrator can handle the value of this global parameter in the Planning application configuration dedicated window.
